1. Field of the Invention
The present invention relates to an image display device that performs display control of pixels by causing light emitting elements such as organic electroluminescence elements to emit light.
2. Description of the Related Art
Some image display devices including organic electroluminescence display devices (hereinafter, referred to as organic EL display devices), which have organic electroluminescence elements (hereinafter, referred to as organic EL elements) as light emitting elements, perform display control of pixels by causing light emitting elements of the respective pixels to emit light. In this type of image display device, a light emitting element is disposed in each of a plurality of pixel areas which are defined by dividing a display area (display screen) into a grid pattern. The light emission of the light emitting elements is controlled on a pixel basis to display an image in the display area.
In order to make the light emitting element in each pixel area emit light at an arbitrary luminance, each pixel is provided with a pixel circuit, which contains a thin film transistor (TFT), a storage capacitor, and the like. Luminance information is written in the pixel circuit by means of signals supplied from the outside through a control signal line and a data signal line, and control is executed to make the light emitting element emit light at a luminance corresponding to the written luminance information.
Examples of the type of pixel circuit that is installed in an image display device are disclosed in JP 2001-035663 A, JP 2001-332383 A, JP 2001-109405 A, and JP 2004-006341 A. In image display devices disclosed in those documents, rectangular pixel areas are defined on a substrate by power supply lines, data signal lines, control signal lines, and the like, and a pixel circuit is disposed in each of the pixel areas to control the light emission of a light emitting element that is provided in the pixel area.
It is desirable that image display devices as those described above have small pixel area size in order to display a high-definition image. However, reducing the pixel area size relatively increases the area ratio of various circuit elements constituting a pixel circuit to the total pixel area. This makes it difficult for the image display devices, especially organic EL display devices and others where the number of circuit elements constituting a pixel circuit is large, to contain the circuit elements within a pixel area.